Variable buoyancy arrangement



United States Patent Inventors Robertl-l. Murphy West Hartford, Connecticut; Julian Gordon, Malden, Massachusetts Appl. No. 766,932 Filed Oct. 11, 1968 Patented Nov. 24, 1970 Assignee The Wiremold Company West Hartford, Connecticut a corporation of Connecticut VARIABLE BUOYANCY ARRANGEMENT 10 Claims, 1 Drawing Fig.

US. Cl. 114/16, 61/69 Int. Cl. B63g 8/14, 863g 8/22 Field 01' Search 1 14/16, 16.3; 9/8; 61/69 AIR 5 dl/RC E [56] References Cited UNITED STATES PATENTS 3,179,962 4/1965 Shear et al. 9/8 3,204,596 9/1965 Fallon 114/16 Primary ExaminerTrygve M. Blix Attorney- Davis, l-loxie, Faithfull & Hapgood ABSTRACT: A variable buoyancy arrangement includes a tank of fixed volume and pressure regulating apparatus for maintaining the interior of the tank within a fixed pressure range above the ambient underwater condition. An air-pressure actuated pump is selectively operable under user control for decreasing buoyancy by inserting water into the tank; and buoyancy may be increased by opening a stop cock to allow expulsion of water from the tank.

7'0 BREATHING APPARA TU! Patented Nov. 24, 1970 3,541,985

INVEN'IORS JUL IAN GORDON 20550? H- Muflpwy VARIABLE BUOYA'NCY ARRANGEMENT DISCLOSURE OF INVENTION This invention relates to equipment carried by a person during his underwater activities to control the aggregate buoyancy of himself and his equipment to enable him to effect a desired buoyancy with respect to the depth of his activities or facilitate his ascent or descent in the water.

For underwater activities such as military demolition and hazard fabrication, salvage and treasure recovery, scuba-explorations and the like, a diver is equipped with an air source for breathing, and typically loaded with sufficient weight to characterize the system comprising the diver and his equipment as having a neutral, or substantially neutral buoyancy. This permits the diver to move about, and to select his vertical water depth under his own physical power while expending energy only to overcome inertia and develop motion, and not to maintain a desired depth once it has been attained.

However, this weight selectionprocess is only approximate at best. Further, when the buoyancy forces acting on the diver change, e.g., by decreasing when the volume of the diver and his equipment decreases under the influence of increased water pressure at greater depths, normally referred to as .suit squeeze, or by increasing when the weight of the diver and his equipment decreases as.his air is consumed (typically a change of several pounds), the diver is forced to reduce or add to his weighting (or to change the volume of his equipment) to maintain a neutral buoyancy. This is often accomplished by picking up rocks from the water bottom and carrying the rocks about, clearly a cumbersome and insecure-procedure.

Further, a diver must often swim significant distances at water level to go to and from a starting point such as an anchored craft to the desired diving area. Thus he must expend considerably energy swimming on the surface in a buoyancy condition much better suited to underwater swimming.

. lt is thus an object of the present invention to provide improved underwater maneuvering apparatus.

More specifically, an objectof th' present invention is the provision of apparatus for selectively varying the buoyancy of the diver and his apparatus without employing cumbersome weighing elements.

These and other objects of the present invention are realized in an illustrative variable buoyancy-control apparatus adapted to bephysically carried by the diver during his underwater activities. The apparatus includes a tank of fixed volume having as one input thereto a valve configuration for supplying air characterized by a pressure within a fixed range above that of the ambient environment. A three-way, push button actuatedlvalve is employed to selectively actuate a ment there shown includes a tank 12 which is adapted to exhibit a constant volume when the inside thereof is pressured. The tank 12 may thus be fabricated either of a rigid material such as metal or a hard synthetic plastic, or of an air-inflatable material such as canvas which will not stretch beyond a fully v expanded volume. Any desired shape will suffice for the tank 12, although a form contoured for comfortable mounting'on the back ofthe user about the user's air supply cylinder is most convenient.

To supply air under higher than ambient underwater environmental pressure, an air source 10 is provided. In the preferred form illustrated, this is the main air cylinder carried for underwater breathing purposes which commonly contains air under a pressure of several hundred pounds per square inch. Before reaching the tank 12, the high pressure air undergoes several ressure reductions as follows. The source 10 is connected to a pressure regulating valve 15 of conventional form which reduces the air pressure, e.g., to about 100 pounds per square inch above the ambient underwater pressure for delivery to two branch conduits, one 16 leading to the user's breathing apparatus and the other 17 leading to an additional pressure regulating valve 20. Since the pressure of the air leaving the first pressure valve 15 is still too high for use in the.

buoyancy control devices, the second pressure reduction valve 20 further reduces the pressure, e.g., to about 15 p.s.i. above ambient. From the exit port of second valve 20 two branch tubes 21'and 22 conduct the air, on one hand to the final pressure reduction valve 28 (in pipe 21) to the tank 12, the reduction being to about 5 p.s.i. above ambient pressure or 10 pounds below the supply which isregulated at 15 pounds above ambient. Alternatively, the valve 28 may also be of the water pump, with the pump being responsive to each depression of the valve button to force a fixed quantity of water into the tank chamber. An output conduit is connected to the tank for selectively passing water outward therefrom, under control of a stop cock valve, with the water being discharged under the action of the above-ambient internal tank pressure when the stop valve is open.

The user of the above apparatus may decrease his buoyancy as changing conditions from timeto time dictate by depressing the valve actuating button, thereby causing the pump to force additional water into the tank chamber. Since the chamber is of fixed volume, the additional water supplies an incremental downward force while causing no additional water displacement thus not increasing the upward buoyancy force acting on the diver. Correspondingly, to increase the system buoyancy by a desired amount, the stop cock is opened and water is forced out of the pressurized chamber, thus reducing the system weight, but not its volume. Swimming along the water surface is facilitated since the chamber can be purged of water and thus act as a flotation aid.

A complete understanding of the present invention, and of the above and other features and advantages thereof may be 'cy tank 12 at its desired pressure.

regulating type to develop the requisite 5 p.s.i. above ambient. Thus, the branch 21 supplies air under pressure to the buoyan- The other branch 22 from the second pressure reduction valve 20, is provided to supply air pressure to a system for controlling and adjusting the amount of water in the tank 12 to decrease its buoyancy. This is done selectively by providing in tube 22 a conventional two-position button-actuated valve 30 to one exit port of which is connected a tube 33 leading to an air-pressure actuated pump 50. The valve 30 normally is biased asshown in the drawing to connect the conduit 33 to a vent tube 35 exposed to the underwater environment. The valve has a button 31 which when pressed by the user interconnects the tubes 22 and 33. When the button 31 is released the return of the valve plunger34 to normal position reconnects the tubes 33 and 35 while blocking the conduit 22. Suitable embodiments for the valves 15, 20, 28 and 30 discussed hereinabove, as well as additional valve elements considered below, are well known to those skilled in the art, and these devices need not be described further.

The pump 50 includes a housing 51 having an "air port at one end and a water port at its opposite end, also has therein a piston or a flexible diaphragm 52 biased upward, Le. toward its air" end by a compression spring 54. Water may selectively flow into the pump housing 51 through its water', end, water" end, i.e. beneath the diaphragm 52 through the entrance port 56 ofa one-way check valve 58 whose exit port is connected by a conduit 60 to the pump's water end. When the button 31 of the pump controlvalve is depressed, compressed air at 15 p.s.i. above the underwater ambient pressure flows through the elements 22-30-33 to the pump 50, thereby forcing the diaphragm 52 to the downward position 52 as shown in a dashed line in the drawing. This forces out of the pump a fixed quantity ofwater defined by the volume between the diaphragm in its up and down positions 52 and 52'. To deliver this volume of water to tank 12, a branch 61 from the conduit 60 connects to the inlet of a one-way check valve 64 whose outlet is connected by a conduit 65 to tank 12. The unidirectional nature of the check valves 58 and 64 prevent discharge of water from the pump except to the tank, and prevent flow of water from the tank back into the pump.

When the button 31 is released, the tube 22 is blocked by the valve 30, and the area above the diaphragm 52 is vented to the ambient environment through the conduits 33 and 3S. Accordingly, with the pump actuating air pressure thus removed, the compressed spring 54 pushes the diaphragm 52 to its quiescent raised position. This motion of the diaphragm 52 creates a reduced pressure in the lower portion of the pump 50 which draws water therein through the check valve 58 and the conduits 56 and 60. The pump 50 is thus charged and in a primed condition to discharge a like quantum of water in the tank 12 when the valve 30 is again actuated by the button 31.

To selectively remove waterfrom the tank 12, a conduit 72 1 having a normally closed stop cook valve 74 affixed thereto is connected to the tank 12. When the stop cock valve is opened, the internal pressure in the tank 12 which is always at least 5 p.s.i. above the external ambient pressure forces water out of the tank through the elements 72-74.

'Finally, a pressure relief valve 70 is connected to the tank 12 and adapted to open when the internal pressure ofthe tank 12 exceeds a predetermined pressure level above ambient, which pressure level is intermediate the pressures developed by the valves 20 and 28 e.g., l p.s.i. above ambient. This fixes the maximum internal pressure of the tank 12 at 10 p.s.i. above ambient, thus constraining the pressure within the tank 12 to always be in the range between -10 p.s.i. above ambient. This, in turn, assures that the 15 pounds pressure (above ambient) which actuates the pump 50 will always be sufficient to overcome the internal tank pressure and drive water into the tank 12 each time the button 31 is depressed, and further ensures that the internal pressure of the tank 12 is sufficiently greater than the ambient pressure to force water out of the tank 12 into the local environment when the stop cock valve 74 is opened.

The-button 31 and the stop cock valve 74 are advantageously mounted in a convenient location readily accessible for user control. if desired, a two-position valve 20 embodying a remote controlactuating mechanism in place of the valve button 31 may be employed, with the remote control mechanism being contained in a place convenient for the user and the remainder ofthevalve 30 being located as desired.

With the above arrangement in mind, an illustrative sequence of operationv will now be described. A diver just beginning his journey starts with his tank 12 substantially free of water and with an internal pressure of 5 pounds per square inch above ambient, as produced by the high pressure air supply acting through. the regulating valves and and the reducing valve 28. The user swims on the water surface to the diving area with the empty tank 12 being a flotation aid and not an encumbering weight which has to be transported.

At the diving location, the diver repeatedly actuates the button 31.to change his status from positive to neutral or slightly negative buoyancy. With each depression of the button 31 the pump 50 responds in the above-described manner to air pressure from the 15 p.s.i. above ambient regulator valve 20 acting through the conduits 22 and 33 and the valve 30 by forcing a fixed quantity of water through the path 60-64-65 into the tank 12. Since the tank 12 is of a fixed volume it displaces a fixed volume of water when submerged. Thus when any water is introduced into the tank by the pump 50, it directly subtracts from the buoyancy forces acting on'the user and his submerged equipment.

At neutral or slightly negative buoyancy, the diver is free to move about under water as he desires without expending energy to maintain his underwater depth. As the buoyancy of the diver and his equipment decreases, e.g., because ofthe increased water pressure as he moves to greater depths, he may compensate by releasing some of the water pumped in at the surface to begin his dive, and as his buoyancy increases because the user expends his air supply or moves to shallower Since the valve system 15- 20-28 develops an output air pressure measured on an ambient, environmental-responsive basis, all pressure relationships are maintained, including the relatively small, 10 p.s.i. maximum gradient between the interior of the tank 12 and the water pressure on the outside thereof. Accordingly, the tank is not crushed at great water depths, even when fabricated of materials which are not naturally form-retaining or do not possess sufficient mechanical strength to retain the form of the tank at ambient underwater pressures.

When the diver wishes to increase his buoyancy, either as an assistance in rising or to correct for an overweighted condition, he opens the stop cock 74 for a desired interval. The element 74 opens and the'air pressure within the tank 12, being in the range of 5-10 p.s.i. above the external water pressure, forces water out of the tank through the conduits 72 and the valve 74. Thus the downward weight force acting against the upward buoyant force is decreased.

1f the stop cock 74 is left open for an extended period, the diver will become underweighted, and rise to the surface. The orifice of the stop cock 741s thus preferably sufficiently small to prevent the rate of ascent of from becoming too rapid, thus avoiding any potentially dangerous decompression problems.

During an ascent, the ambient pressure will reduce until it becomes 10 p.s.i. less than the pressure within the tank. Then the relief valve 70 will open; Air will exhaust from the tank 12 through the valve 70 to maintain the 10 p.s.i. tank-water pressure differential.

Thus, the variable buoyancy arrangement depicted in the drawing and discussed in detail above is readily operable under control of the user to generate any desired buoyancy condition for the user and his equipment vis-a-vis the surrounding underwater environment.

The above-described arrangement is only illustrative of the principles of the present invention. Numerous modifications and adaptations thereofwill be apparent to those skilled in the art, withoutdeparting from the spirit and scope of the present invention. For example, this apparatus may be used to help a diver carry heavy objects picked upon the bottom, or it may be attached to such heavy objects he wishes to transport and it will then maintain their buoyancy regardless of their changing depth without the instability inherent in buoyancy tanks open to the sea".

We claim:

1. In combination in a variable buoyancy arrangement adapted for underwater activity, a tank of substantially fixed volume for selectively storing water, means for selectively supplying compressed air to said tank and for selectively venting air from said tank for maintaining the interior of said tank within a predetermined pressure range above the underwater ambient pressure, means for selectively introducing water into said tank, and means for selectively discharging water from said tank.

2. A combination as in claim 1 wherein said selective water introducing means comprises a pump having a discharge port connected to said tank, a source of air at a pressure greater than the maximum pressure within said tank, and valve means for selectively energizing said pump to cause introduction of water into said tank.

3. In combination in a variable buoyancy arrangement adapted for underwater activity, a tank of substantially fixed volume for selectively storing water, means for maintaining the interior os said tank within a predetermined pressure range above the underwater ambient pressure range above the underwater ambient pressure means for selectively introducing water into said tank, means for selectively discharging water from said tank wherein said selective water introducing means comprises a pump having a discharge port connected to said tank, a source of air at a pressure greater than the maximum pressure within said ta'nk, valve means for selectively energizing said pump tocause introduction of water into said tank, wherein said pump comprises a pump housing, piston means movable within said housing, means for biasing said piston means, and means for connecting one side of said piston means to said air source, the other side of said piston means communicating with said pump discharge port.

4. A combination as in claim 3 further comprising a check valve connected between said pump and said tank.

5. In combination in a variable buoyancy arrangement adapted for underwater activity, a tank of substantially fixed volume for selectively storing water, means for maintaining the interior ofsaid tankwithin a predetermined pressure range above the underwater ambient pressure, means for selectively introducing water into said tank, means for. selectively discharging water from said tank wherein said selective water introducing means comprises a pump having a discharge port.

connected port connected to said tank, a source of air at a pressure greater than the maximum pressure within said tank, valve means for selectively energizing said pump to cause introduction of water into said tank, wherein said tank pressure maintaining means includes pressure regulating means connected to the compressed air source providing a pressure of a predetermined value greater than the underwater ambient pressureand pressure reducing means connecting said pres sure regulating means with said tank, and means for connecting said pressure regulating means to said pump.

6. A combination as in claim 5 further comprising pressure relief valve means connected to said tank.

7. A combination as in claim 5 wherein said selective discharge means comprises a stop cock connected to said tank.

8. A combination as in claim 1 wherein said selective discharge means comprises a stop cock connected to said tank.

9. ln combination in a variable buoyancy arrangement adapted for underwater activity, a tank of substantially fixed volume for selectively storing water, means for maintaining the interior of said tank within a predetermined pressure range above the underwater ambient pressure, means for selectively introducing water into said tank, means for selectively discharging water from said tank wherein said selective water introducing means comprises a pump having a discharge port connected to said tank, a source of air at a pressure greater than the maximum' pressure within said tank, valve means for selectively energizing said pump to cause introduction of water into said tank, wherein said pump comprises a pump housing, a diaphragm attached to said housing, means for biasing said diaphragm, and means for connecting one side of said diaphragm to said air source. the other side of said diaphragm communicating with said pump discharge port.

10. The combination as claimed in claim 2 having a connection between said valve means and said air source for energizing said pump as said valve means is operated.

C 'lJ J (5/50) Y 1 w w n r C581 11* ILAI h 0 CORnEC MON P t n 3 541 935 m1ember. 2 4 ..1910

n fl Robert H. Murphy & Julian Gordon It is certified that error appears in the above--ident1 fied patent and that said Letters Patent are hereby corrected as shown below:

Col. 1, line 36, "considerably" should be --considerable-.

Col. 3, line 17, "cook" should be --cock--.

Col. 3, line 41, "20" should be --30-.

Col. 4, line 26, delete "of" (second occurrence) Col. 4, claim 3, line 4, "as" should be --of--;

line 5, after "pressure" insert a comma ar delete "range above the";

line 5, delete "underwater ambient pressuz Col. 5, line 17 (claim 5, line 9) after "connected" (first occurrence) de1ete"port connected".

Signed and sealed this 30th day of March 1 971 (SEAL) Attest:

EDWARD M.FLETGHER,J'R. WILLIAM E. SGHUYLER, J; Attesting Officer Commissioner of Patent 

